With their Reagan-era radios now retired, the Capitol Police have begun communicating over a modernized, encrypted digital radio system.

The long-delayed upgrade means better signal strength, less static and the end of the “dead zones” that once hindered communication in the Capitol’s thick-walled tunnels and parking garages. It will also prevent outsiders from listening in on the force’s transmissions via cheap scanners.

Capitol Police Chief Kim Dine deemed the transition a “significant milestone” for the department in a release issued Thursday.

The radio modernization project began in 2006, before Dine took the helm. Since then, Congress has appropriated more than $106 million to fund the upgrade, with $103 million currently obligated.

House Legislative Branch Appropriations Subcommittee Chairman Tom Cole, R-Okla., said he was pleased that both chambers worked together to “fund that need, even in a tough budget requirement.

“There’s nothing more important than keeping the Capitol safe, not only for the people that work here but obviously for the visitors we have every day,” said Cole, who took the gavel in 2013.

The department has been talking to Congress about the need to modernize for close to a decade. A 2004 cost estimate of $35 million for the project was limited to upgrading the old analog system and did not include the new digital technology or infrastructure required to cover the Capitol campus, plus a 10-by-10 mile outdoor grid.

“I am so pleased that the Capitol Police interoperable radio system was fully implemented this week,” Rep. Debbie Wasserman Schultz, ranking member and former chairwoman of the panel, said in a statement. “As I’ve said in several Legislative Branch oversight hearings over the last six years, this new system will be absolutely critical to the safety and security of the Capitol campus and has been desperately needed since the attacks on 9/11. I commend Chief Dine and his team for their perseverance to get the new radio system operational.”

The Capitol Police teamed up with Architect of the Capitol Stephen T. Ayers and Naval Systems Air Command in designing, implementing and executing the system. The Government Accountability Office played a key role in technical and project management aspects of the upgrade.

The new system is aimed at providing greater “interoperability” — a term that became something of a buzzword around Capitol Hill in the wake of the Navy Yard shooting and the Oct. 3 incident involving Miriam Carey on the Senate side of the Capitol campus. Members of Congress questioned whether enhanced radio interoperability among officers from the Capitol Police, Metropolitan Police Department and Secret Service could have saved lives.

Sen. John Hoeven, R-N.D., advocated for the radio modernization project as ranking member of his chamber’s Legislative Branch Appropriations panel. He made the project a priority in the interest of security for members, their staffs and the thousands of visitors who come to the complex each day, according to spokesman Don Canton.

Dine thanked Congress, especially the Appropriations and Oversight Committees, for their collaboration. He said it will be a “state-of-the-art critical life and safety too for our agency.”